From oily fish to whole grains, find out how food affects your mental well-being. Photo / 123rf
‘Nutritional psychiatry’ is the study of how food can improve your mood. Here’s everything you need to know…
The old adage, you are what you eat, applies to both our body and mind. “There’s no doubt that food and mood are really closely connected,” says Dr Federica Amati, the head nutritionist for Zoe, the nutrition science company set up by Professor Tim Spector. “For example, we know that food and dietary patterns are really important in helping to prevent mental health disorders, but also in improving their symptoms. We also know they can help with sleep and energy levels, both important markers of mental health.”
There is no silver bullet when it comes to food and brain health according to Sarah Berry, an associate professor in nutritional sciences at King’s College London: “Improving brain health is down to overall dietary patterns, rather than single foods. We need to eat a wide variety of nutritional foods, because a diverse diet contains lots of different chemicals that all work together to improve health.”
A recent study published in Nature Mental Health journal backed this up, and found when it comes to brain health, nothing beats a balanced diet. Dr Wei Cheng, one of the study’s authors at Fudan University in China said, “People who ate a more balanced diet had better ‘fluid intelligence’ [the ability to problem solve] and better processing speed, memory and executive functions [which include things like organisational skills and attention].”
However, says Berry, “there are some magic ingredients in certain foods that really can help our brains”.
Oily fish such as salmon are full of omega-3 fatty acids, which are a type of fat your body can’t produce on its own so you have to get it from your diet. They’re important for your heart and immunity, but also your brain health.
One study from the International Society for Nutritional Psychiatry Research found that omega-3 supplements containing EPA and DHA (two types of omega-3s) improved symptoms of depression and may also help prevent it. Other good sources of omega-3s include herring, sardines, mackerel, anchovies, chia seeds and walnuts.
“Nuts and seeds are a powerhouse of nutrition and packed with polyphenols and nutrients, which impact brain health,” says Berry. Polyphenols are micronutrients occurring naturally in plants, and growing evidence has linked them to cognitive function and brain wellness.
“Walnuts are particularly good,” says Amati. A 2020 study published in the journal Nutrients found that eating walnuts led to improvements in memory and brain functioning. However, all nuts and seeds have been linked to slower cognitive decline, and a 2021 study found people at risk of cognitive decline, such as a family risk of Alzheimer’s, had better outcomes if they ate more nuts – specifically walnuts.
All green leafy vegetables, such as broccoli, cabbage, pak choi and asparagus are packed with nutrients and fibre, which have been linked to slower cognitive decline. A study at the University of Illinois involving middle-aged adults found those with higher levels of lutein, a nutrient found in kale and spinach, had younger brain responses than their peers, which led the researchers to believe that lutein may play a protective role against age-related cognitive decline.
But don’t stop at kale and spinach. A 2022 study from Israel found those who followed a diet rich in leafy greens, green tea (and, again, walnuts), showed the slowest rate of age-related brain decline – while those who followed a less plant-based diet had greater brain ageing.
“Don’t think you need to cut back, because coffee supports cognitive function,” says celebrity nutritionist Gabriela Peacock, author of 2 Weeks To A Younger You. A January 2024 study by UK Biobank found two to three cups of coffee or tea per day reduced dementia risk by up to 28 per cent.
“Caffeine is full of antioxidants that protect the neurons in our brains from everyday wear and tear,” says Peacock. “However, two or three creamy lattes containing sugar will quickly reduce its benefits, so have a good quality Americano [black coffee] with a splash of milk instead.”
One drink you should cut back on is wine. “Alcohol is a neurotoxin,” says Dr Amati. “Societally and culturally it’s part of our lives, but we should be mindful of the effects of alcohol on our brains, particularly as we get older. People over 70 become less efficient at processing alcohol, and there’s some compelling data that show too much alcohol in later life can increase the risk of dementia. Reducing alcohol content as we get older is important.”
Your brain naturally produces neurotransmitters, which are designed to elevate your mood, but they “sometimes need a helping hand”, says Gabriela Peacock. “The nutrient L-theanine induces calm by stimulating serotonin and GABA, two neurotransmitters that soothe anxiety and increase happiness.” Black tea and in particular green tea contain L-theanine, which can also improve the quality of our sleep (which has been shown to promote good brain health).
In recent years the link between gut health and mental health has been well documented, with one study from South Korea finding that people who ate more gut-friendly probiotic foods had fewer episodes of depression. While a study in 2022 from University College Cork in Ireland found that eating fermented foods, which improve gut health, can make us feel less stressed.
Explaining the link, study author Professor John Cryan said it “could be via the relationship between our brain and our microbiome [the trillions of bacteria that live in our gut]. Known as the gut-brain axis, this allows the brain and gut to be in constant communication with each other”. Gut-friendly probiotics include kefir, sauerkraut, kimchi and kombucha, and can be found in most health food stores and supermarkets.
In a 2023 study published in the journal Neurology, researchers found those who ate three or more servings of whole grains per day had a slower rate of cognitive decline and memory compared to those who ate fewer than one serving per day. “Whole grains are one of my favourite food groups for good brain health,” says Amati. “Hardly anybody eats enough of them, but a simple swap might be having wholegrain pasta with your spaghetti bolognese, or swapping white rice for pearl barley, which tastes delicious.”
Known for its slightly furry texture and musky taste, this green-grey herb is often used in Italian or British cooking. And it can also be good for our brain health. Researchers at Northumbria University have found that sage, as well as ginseng, lemon balm and rosemary, have all improved mental performance. David Kennedy, a professor of biological science and director of the brain, and who worked on the studies, says: “We have consistently seen immediate improvements in brain function with sage and other herbs.”
Finally, Amati says extra virgin olive oil, which is rich in polyphenols, is beneficial to brain health. A Yale University study found that the extra virgin kind enhances brain connectivity, however Amati says the cheaper virgin version is also beneficial. And even a drizzle will help.
According to a study from Harvard T. H. Chan School of Public Health, consuming just half a teaspoon of olive oil per day is enough to reduce your risk of dying from dementia by 28 per cent.
Anne-Julie Tessier, who worked on the research, says: “Our study reinforces dietary guidelines recommending vegetable oils such as olive oil and suggests that these recommendations not only support heart health but potentially brain health, as well.”
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